This reverts commit 6047e3ce.

Warning push/pop support has been added to GCC in version 4.6.0,
and pragmas to ignore certain warnings are present since 4.2.0.
This patch hides the compiler-specific warning push/pop/disable
pragmas behind a macro-based implementation (currently for MSVC and
clang /GCC.

This avoids warnings, as seen e.g. on GCC 4.4:
  ../../include/rapidjson/document.h:14: error: expected [error|warning|ignored] after ‘#pragma GCC diagnostic’
and earlier versions complaining about unknown pragmas being ignored.

Note: unittest.h and perftest.h need to check for compilers
explicitly, as rapidjson.h is not included there.

Can write d.Parse(...) instead of d.Parse<0>(...)
Hope to reduce strangeness and confusion for beginner.

git-svn-id: https://rapidjson.googlecode.com/svn/trunk@67 c5894555-1306-4e8d-425f-1f6f381ee07c

git-svn-id: https://rapidjson.googlecode.com/svn/trunk@36 c5894555-1306-4e8d-425f-1f6f381ee07c

git-svn-id: https://rapidjson.googlecode.com/svn/trunk@35 c5894555-1306-4e8d-425f-1f6f381ee07c

git-svn-id: https://rapidjson.googlecode.com/svn/trunk@30 c5894555-1306-4e8d-425f-1f6f381ee07c

git-svn-id: https://rapidjson.googlecode.com/svn/trunk@28 c5894555-1306-4e8d-425f-1f6f381ee07c

Added multiple platform specific file I/O performance tests
Added CheckSum() in platform test as baseline of parsing speed, which should be more appropriate than strlen().

git-svn-id: https://rapidjson.googlecode.com/svn/trunk@26 c5894555-1306-4e8d-425f-1f6f381ee07c

Proved FileStream is very slow due to fgetc(). Added a new FileReadStream which uses fread() with buffer.

git-svn-id: https://rapidjson.googlecode.com/svn/trunk@22 c5894555-1306-4e8d-425f-1f6f381ee07c

git-svn-id: https://rapidjson.googlecode.com/svn/trunk@2 c5894555-1306-4e8d-425f-1f6f381ee07c