Change Fengari path parsing

[comicallynathan]

Issue: analyse_requires.js uses some sort of string parsing to resolve the path. However, it returns an error:

Module build failed (from ./node_modules/fengari-loader/src/fengari-loader.js):
Error: Cannot find module '/defs.js'

Solution: I've removed the parsing and replaced fengariPath as "fengari/src" where require(${fengariPath}/defs.js); becomes require("fengari/src/defs.js");. The console doesn't return an error, and the compiler works.

Next step: Due to compatibility, analyse_require.js should follow the solution that I provided.