[HACKY FEATURE] Expose __readFileSync to sandboxed code

This is for testing only.
This now uses a specific manifest file format to grant permissions to sandboxed code.
This should be cleaned up if it continues to be used.
[FIX] Filesystem logic for complicated paths

    Previous verison was not matching file and module paths correctly
    Pulled out some functionality into separate functions
[TASK] Remove console.log statement
[FIX] Print errors to console
[HACKY FEATURE] Expose Int32Array in sandbox for bitcoinjs
[TASK] Changed logging
[FEATURE] Made filesystem simpler (moved logic out)
[FIX] Error logging
[TASK] Add manifest to FileSystem instance
[FEATURE] Provide Buffer to sandbox
[FEATURE] setImmediate, setTimeout
[FIX] Remove Buffer module
[FEATURE] Optionally supply output_stream
[TASK] Remove console.log statement