bslim_printer: Support printing StringRef values.

Printing `bslstl::StringRef` values was not previously supported
because the type does not contain a `print()` method and also does
not declare the `bslalg::HasStlIterators` type trait due to not
fulfilling the requirements.  Since `StringRef` values should print
enclosed in quotes similar to `bsl::string` values, support printing
them directly and defer to `StringRef`'s `operator<<` implementation.
bsls_timeutil: Support Mach high-resolution monotonic clock.

Adds platform-specific support for the Mach kernel high-resolution
monotonic timer when BSLS_PLATFORM_OS_DARWIN is defined.
Adjust some documentation, and simplify assertion
Update and test assertion logic
Add uses of bsls_assert and bsls_once
Fix OSX build issues
Update interface of decimal64From*Encoding to take const char *

Update the interfaces of 'decimal64FromMultiWidthEncodingRaw',
'decimal64FromMultiWidthEncoding', to take a 'const char *' buffer as
the input parameter.  Update the interface of
'decimal64FromVariableWidthEncoding' to take a 'const char *' as the
input parameter and the return value.
Apply changes to documentation.
Fix build issue
Add tests to ImpUtil for BinaryIntegral conversion

The current tests assume a 'BID' implementation (and thereby a
memcmp/memcpy-like semantic) in the testing.  When universal
'BID' conversion is implemented, these tests will be replaced.
Added a missing header for dfp tests on Windows.

The windows build failed for want of 'stdlib.h'.
Silence "GCC" pragma warnings in intel wrappers.

The inteldfp wrapper code had spurious "#pragma GCC" lines to disable
GCC warnings that were causing warnings on other platforms.  These
pragmas are now moved inside of a GCC conditional block.
Test 'inteldfp' symbol visibility only on Linux.

The IBM platform fails to build the intel test driver with new
symbol visibility tests.  This is due to a spurious redefnition of
'NAN'.  These tests are now performed only on the Linux platform.
This should not be a problem , as we're testing the viability of a
compiler, and not the functionality of a component.
Renamed [To|From][DenselyPacked|BinaryIntegral].

The [To|From][DenselyPacked|BinaryIntegral] conversion functions
were ugly and misleading (as "Integral" wasn't converting to an
integer).  They've been renamed to "[To|From]BID" and "[To|From]DPD",
which less ambiguously describe their function.
Rebase decimal-errata-fixes

Rebase the decimal-errata-fixes branch on top of commits that adds
support for variable and multiwidth encodings in
bdlpdfp_decimalconvertutil.

Fix some stylistic problems.
[APPROVAL] pending/master/decimal-errata-fixes to master
[APPROVAL] pending/master/bslim-printer-stringref-drqs-58996420 to master
Fix decimalFromNetwork return value

Update the implementation to one last byte read from the buffer instead
of one past the end past of the memory storing the decimal value.

Update the type of the return value to 'const unsigned char*' instead of
'usigned char*'.

Fix minor issue in function contract.
[APPROVAL] pending/master/fix-decimalfromnetwork-drqs-59157247 to master
[APPROVAL] pending/master/mach-monotonic-clock-drqs-47763030-rebase to master