Removed unnecessary include paths. Removed the dependency on unistd.h. Moved the generated files to intermediate directory so that the source is not polluted.

These changes only affect the gyp build system because they required flex-bison options that are not supported by old binaries in compiler/tools. Another reason to switch to gyp build system.
Review URL: http://codereview.appspot.com/994041

git-svn-id: https://angleproject.googlecode.com/svn/trunk@186 736b8ea6-26fd-11df-bfd4-992fa37f6226