add CMakePushCheckState.cmake for older cmake versions

http://cmake.org/gitweb?p=cmake.git;a=blob;f=Modules/CMakePushCheckState.cmake
with licence copied from:
http://cmake.org/gitweb?p=cmake.git;a=blob;f=Copyright.txt
use absolute path for referencing doc dir
Update debian build scripts:

- fix a warning by lintian
http://lintian.debian.org/tags/description-synopsis-starts-with-article.html
- Correct package name to properly include soname (librabbitmq1)
- Correct shared libs dependancies