This adds compression of bitmap in PUAN. The compressed bitmap
is used only if the number of bits in the bitmap does not fit in
the message and there is a gain after compression.
The algorithm is part of libosmocore and so there is dependency
on the libosmocore for compilation.
The algorithm is tested on integration setup by forcing compression.
Change-Id: Id2eec4b5eb6da0ebd24054b541b09b700b9b40ba