Remove XLC-specific #ifndefs from bslstl_list case 14
fixed typo per DRQS (and a couple of others)
fixed typos per DRQS
bsls_annotation: _CMP_CLANG and documentation fix

Explicitly add mention and support for 'BSLS_PLATFORM_CMP_CLANG'
instead of relying on 'BSLS_PLATFORM_CMP_GNU' to be set since Clang
supports the full set of GCC attributes.

Fix documentation to add _USED and _UNUSED to @MACROS list.
Supports building with a mingw32 toolchain.

Requires minimal changes to 'bsls_platform' detect if the toolchain is a GNU
toolchain but running on windows.
Create bsls_byteorderutil, bsls_byteorderutil_impl
bsls_byteorderutil{,_impl} -- add #include to fix nightly build
Added += operator for StringRefData (and by extension StringRef) that prevents an unnecessary copy
Added tests to verify functionality of += operator that was added
bsls_byteorderutil: Clay's feedback.
Fixes from phabricator review
bsls_byteorder*: Clay's 2nd round feedback.
Added explicit keyword to constructor
Created basic infrastructure for universal hashing (working name still)
Created new bslh package, factored out hashing algorithms, began writing documentation
Finished test driver for one-at-a-time algorithm
First draft of test driver for bslh_hash
Fixed some bde_verify warnings
Fixed some bde_verify warnings
More bde_verify cleanup