Setup barebones of lexer, token, and symbol table.
Merge branch 'master' of https://github.com/saicheems/simplelang

Conflicts:
	src/github.com/saicheems/lexer/lexer.go
	src/github.com/saicheems/simplelang/simplelang.go
	src/github.com/saicheems/token/symbol_table.go