minor: use travis svg shields
CXX-165 Remove recursive mutex to privatize thread local header

Also, a drive by removal of heap checking and FILE/LINE noise
from mutex.h
Typo 'Licencse'=>'License'
CXX-151 Backport server rc2..rc3 changes
CXX-151 As part of RC3 backport, drop signal_handlers.

These files changed significantly between rc2 and rc3, including
pulling in a new dependency on db/client.h, which we had not extracted.

We def. don't want db/client.h and its transitive dependencies, but
as a nice consequence of other edits in rc2..rc3, no files that we
own now depend on signal_handlers.h, so we can drop the dependency,
rather than needing to pull in db/client.h

Note that we have already made this change on the legacy branch. The
driver library shouldn't be in the business of signal handling.
Merge branch '26compat' into legacy

Conflicts:
	README.md
	src/mongo/client/gridfs.cpp
	src/mongo/client/sasl_client_session.cpp
	src/mongo/util/allocator.h
	src/mongo/util/log.h
CXX-167 Standardize driver on boost mutex rather than legacy wrappers
CXX-23 CXX-57 Create a config.h header for ODR affecting macros and create a meaningful version header
CXX-163 Create integration target
CXX-158 Add GridFS integration tests
CXX-159 Add SASL client auth integration test
minor: exampleSourceMap formatiing
minor: scoped_db_conn_test ordering
CXX-163 improve integration target

Move integration tests and associated files under unittest directory
Move client_test_main and integration_test_main under unittest directory
CXX-163 use port parameter and renamings
CXX-163 add licenses
CXX-163 move and rename integrationTestParams
CXX-158 update GridFS tests to use new chunk size
CXX-163 allow parallel builds without parallel test runs