tools: bump library version numbers

tools: bump library version numbers

The following libraries are checked:
1. libxc, version number bumped
2. libxl, version number bumped
3. libxlu, no development in 4.7 cycle, but depends on libxl, version
   number bumped
4. libs/*, new in 4.7 cycle, version numbers not bumped
5. libxenstore, no development in 4.7 cycle, version number not bumped
6. libxenstat, no development in 4.7 cycle, version number not bumped
7. libvchan, depends on  xengnttab library, API changed, version number
   bumped

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
Acked-by: Ian Jackson <ian.jackson@eu.citrix.com>
Release-acked-by: Wei Liu <wei.liu2@citrix.com>