package: hy_package_get_hdr_end().

To download headers only we need to know how long they are. The start is not
actually at zero, it is preceded with sig-header, but it's small (up to 2kb) and
can be used to verify the header itself.

Also, current libsolv does not expose SOLVABLE_HEADERSTART.
subject: work with full reldeps (containing the CMP flags).
selectors: allow selecting provides with full Reldep string.
New version: 0.4.9
build: 0.4.9-1
subject in C: work with full reldeps
moved subject and nevra from python to C
moved TEST_COND macro to iutil-py.h
fixed indentation in subject-py.c
fixed reldep pointer NULL comparison
package: call repo_internalize_trigger in get_files() (RhBug:1062703)
Save the cache atomically. (RhBug:1047087)
Fix vsnprintf SIGSEGV passing "%s" with no va_list args to pool_debug. (RhBug:1064459)

With a help from pmachata@redhat.com.
write_main() should do a better job erroring out on write errors.
write_main() and write_ext(): even on error do not leave the temporary file behind.
Add reponame into selector.
tests: add a negative test for reponame.
New version: 0.4.10
build: 0.4.10-1
sack: write_*() should also check fclose().

suggested by mls.