Fix endian handling for date_time and timeval

bson_append_date_time wasn't doing little endian conversion and
bson_append_timeval was doing it instead of letting
bson_append_date_time handle it (it wraps date_time)

Fix that stuff
added comment to bson_oid_init()
Merge pull request #53 from smila001/added_comment

added comment to bson_oid_init()
atomic: check for __sun and use atomic.h and sun compiler intrinsics.
atomics: add some checks for solaris built in atomics support.
build: link against -lm manually.
context: use atomic int64 abstraction.
yajl: work around isinf not in -lm on Solaris 10.
build: allow libbson compilation on gcc 3.4

This might not work everywhere, but worth some experimentation now since
that is available on Solaris 10. Would be nice to have stuff working
there.
tests: use bson for various test abstractions.
build: improve gcc check.
Merge pull request #54 from hanumantmk/endian

Fix endian handling for date_time and timeval
build: post-release bump (missed it after 0.6.6)
atomic: cleanup atomics handling and add fallbacks using a mutex.
macros: add fallback for MIN and MAX where typeof does not exist.
build: add bson-atomic.c to build
clock: handle no struct timezone on Sun C compiler.
build: add Sun C Compiler to list of compilers (__SUNPRO_C).
build: check for Glibc 2.19 to handle _BSD_SOURCE vs _GNU_SOURCE
atomic: fallback atomics should be volatile