README: Add ubuntu names of required packages
checksum: Treat SHA checksum as SHA1 + remove LR_CHECKSUM_SHA support (RhBug: 998499)
python: Release Python GIL where appropriate (RhBug: 997042)
Add expectedsize param to download functions and datatypes.

If expectedsize is >0 and server reports a differenet size
for the target, then download is not performed.
LRO_URL and LRI_URL changed to LRO_URLS and LRI_URLS
Add GError ** param to lr_handle_setopt, lr_handle_getinfo and lr_result_getinfo.
Fix few compiler warnings
Change order of arguments of lr_handle_setopt, lr_handle_getinfo and lr_result_getinfo
Fix typo in comment
Python: Fix compiler warning
Doc: Fix doxygen comments.
Update python examples
Update python docs
Add glib-2.0 as dependency to librepo.pc