[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/tvm-lowlevel.tolk

@@ -0,0 +1,29 @@
+// A part of standard library for Tolk
+tolk 0.6
+
+/// Usually `c3` has a continuation initialized by the whole code of the contract. It is used for function calls.
+/// The primitive returns the current value of `c3`.
+@pure
+fun getTvmRegisterC3(): continuation
+    asm "c3 PUSH";
+
+/// Updates the current value of `c3`. Usually, it is used for updating smart contract code in run-time.
+/// Note that after execution of this primitive the current code
+/// (and the stack of recursive function calls) won't change,
+/// but any other function call will use a function from the new code.
+fun setTvmRegisterC3(c: continuation): void
+    asm "c3 POP";
+
+/// Transforms a `slice` [s] into a simple ordinary continuation `c`, with `c.code = s` and an empty stack and savelist.
+@pure
+fun transformSliceToContinuation(s: slice): continuation
+    asm "BLESS";
+
+/// Moves a variable or a value [x] to the top of the stack.
+@pure
+fun stackMoveToTop<X>(x: X): X
+    asm "NOP";
+
+/// Mark a variable as used, such that the code which produced it won't be deleted even if it is not impure.
+fun stackMoveToTopImpure<X>(x: X): void         // todo needs to be deleted, check verified contracts
+    asm "DROP";