[Tolk] Completely rework stdlib: multiple files and renaming

- split stdlib.tolk into multiple files (tolk-stdlib/ folder)
  (the "core" common.tolk is auto-imported, the rest are
  needed to be explicitly imported like "@stdlib/tvm-dicts.tolk")
- all functions were renamed to long and clear names
- new naming is camelCase

crypto/smartcont/tolk-stdlib/gas-payments.tolk

@@ -0,0 +1,63 @@
+// A part of standard library for Tolk
+tolk 0.6
+
+/**
+  Gas and payment related primitives.
+ */
+
+/// Returns amount of gas (in gas units) consumed in current Computation Phase.
+fun getGasConsumedAtTheMoment(): int
+    asm "GASCONSUMED";
+
+/// This function is required to be called when you process an external message (from an outer world)
+/// and "accept" it to blockchain.
+/// Without calling this function, an external message would be discarded.
+/// As an effect, the current smart contract agrees to buy some gas to finish the current transaction.
+/// For more details, check [accept_message effects](https://ton.org/docs/#/smart-contracts/accept).
+fun acceptExternalMessage(): void
+    asm "ACCEPT";
+
+/// When processing an internal message, by default, the limit of gas consumption is determined by incoming message.
+/// Functions [setGasLimit] and [setGasLimitToMaximum] allow you to change this behavior.
+/// Sets current gas limit `gl` to its maximal allowed value `gm`, and resets the gas credit `gc` to zero,
+/// decreasing the value of `gr` by `gc` in the process.
+fun setGasLimitToMaximum(): void
+    asm "ACCEPT";
+
+/// When processing an internal message, by default, the limit of gas consumption is determined by incoming message.
+/// Functions [setGasLimit] and [setGasLimitToMaximum] allow you to change this behavior.
+/// Sets current gas limit `gl` to the minimum of limit and `gm`, and resets the gas credit `gc` to zero.
+/// If the gas consumed so far (including the present instruction) exceeds the resulting value of `gl`,
+/// an (unhandled) out of gas exception is thrown before setting new gas limits.
+fun setGasLimit(limit: int): void
+    asm "SETGASLIMIT";
+
+/// Calculates fee (amount in nanotoncoins to be paid) for a transaction which consumed [gasUsed] gas units.
+fun calculateGasFee(workchain: int, gasUsed: int): int
+    asm(gasUsed workchain) "GETGASFEE";
+
+/// Same as [calculateGasFee], but without flat price (you have supposed to read https://docs.ton.org/develop/howto/fees-low-level)
+fun calculateGasFeeWithoutFlatPrice(workchain: int, gasUsed: int): int
+    asm(gasUsed workchain) "GETGASFEESIMPLE";
+
+/// Calculates amount of nanotoncoins you should pay for storing a contract of provided size for [seconds].
+/// [bits] and [cells] represent contract state (code + data).
+fun calculateStorageFee(workchain: int, seconds: int, bits: int, cells: int): int
+    asm(cells bits seconds workchain) "GETSTORAGEFEE";
+
+/// Calculates amount of nanotoncoins you should pay to send a message of specified size.
+fun calculateMessageFee(workchain: int, bits: int, cells: int): int
+    asm(cells bits workchain) "GETFORWARDFEE";
+
+/// Same as [calculateMessageFee], but without lump price (you have supposed to read https://docs.ton.org/develop/howto/fees-low-level)
+fun calculateMessageFeeWithoutLumpPrice(workchain: int, bits: int, cells: int): int
+    asm(cells bits workchain) "GETFORWARDFEESIMPLE";
+
+/// Calculates fee that was paid by the sender of an incoming internal message.
+fun calculateOriginalMessageFee(workchain: int, incomingFwdFee: int): int
+    asm(incomingFwdFee workchain) "GETORIGINALFWDFEE";
+
+/// Returns the amount of nanotoncoins current contract debts for storage. ("due" and "debt" are synonyms)
+/// If it has no debt, `0` is returned.
+fun getMyStorageDuePayment(): int
+    asm "DUEPAYMENT";