Deprecated old strings in favor of libstr_string. Fixes #24.

Signed-off-by: Christian Gunderman <christian@gundermobile.cwru.edu>
Implemented char lexer/compiler type #18, fixed escape string bug.

Signed-off-by: Christian Gunderman <christian@gundermobile.cwru.edu>
Removed escape_string() debug print statement

Signed-off-by: Christian Gunderman <christian@gundermobile.cwru.edu>
Implemented string_set_char_at()
Also converted string_char_at() to use new char number type.
Implemented char_to_string().

Signed-off-by: Christian Gunderman <christian@gundermobile.cwru.edu>
Merge https://github.com/gundermanc/gunderscript
Attempted implementation of file IO