Refactored the way symbol tables are initialized and stored. This was done in response to the addition of EShSpec.
Symbol table entries depend on three things - language, spec (not now but may eventually), and built-in resources.
We used to build two global symbol-tables - one for each language. During each compile, one of the symbol table was
copied and resource-specific stuff was added. I have moved the symbol table to TCompiler that gets initilized when
compiler is created and reused for each compile. This makes it much cleaner and extensible in case a spec requires
special entries to be added to the symbol table.

PS: Sorry for the long CL, but all of it needed to be done in one CL. I have verified that everything still compiles
and passes all conformance tests.
Review URL: http://codereview.appspot.com/1864044

git-svn-id: https://angleproject.googlecode.com/svn/trunk@351 736b8ea6-26fd-11df-bfd4-992fa37f6226