Add pkgconfig into the corresponding deb and rpm.
Fix build errors in HP-UX 11.31
Fix tests incorrect compilation in Windows with code page 936.
Add cmake option DISABLE_TREE to disable building yajl_tree.c
Install yajl shared library into bin in Windows.
Fix compilation warnings and errors by GCC 3.4.6 and GCC 4.3.6 in Solaris 9.