First pass at cleanup for bdeverify

Currently there are still around 6400 warnings, although a large number
of these should resolve as false positives in a new iteration of
bdeverify in a few days.  Another large set are repeated warnings
about a lack of documentation each time a template is instantiated
and while these must be addressed, it will be easier to see and
address such issues once the false-positives are eliminated.
mend
Hashtable cleanups from bdeverify
mend
Unbreak the dev-integration build

Previously tried to satisfy bde_verify alloctor-propogation issues by
providing a partial specialization of 'bslma::UsesBslmaAllocator' for an
implementation class nested inside the 'HashTable' template.  Unfortunately
this is not valid C++ syntax, so apply the nested trait idiom instead,
where the primary template can deduce the correct behavior without
requiring an additional specialization.
Further bde_verify updates for hash tables

This takes a proper attempt at cleaning up the bde_verify issues associated
with trying to flag allocator usage for a nested class within a class
template.

This fix moves the nested class outside the primary class template, which
solves a number of isses.  Ths documentation is now more conventional,
the nested trait problems go away, and we no longer need to work around
the MSVC bug that did not recognize the out-of-line definitions of the
methods of a nested class (in a class template).
Apply phabricator feedback to hash table
More review comments from Hyman
Added a necessary include for decNumber dependency.

There are forwarding functions to decNumber functionality in
bdldfp_decimalutil.  These functions need to include the
requisite 'bdl+decnumber' header, such that they will properly
compile.  The original source of the decNumber implementation
names was a transitive include dependency from
'bdldfp_decimalimplutil.h'.

This should allow the various quanta (and other) functions in
'bdldfp::DecimalUtil', which rely upon 'bdl+decnumber' to
compile, even when IBM hardware modes are enabled.
Activate hardware flags.

Activate the #if-else structure for BSLS_PLATFORM.
Merge remote-tracking branch 'remotes/origin/dev/amartin172/decimal-util-include-fix' into hardware_code_3
Fix a typo in C99 constants.
Add #include<iostream.h> when in BDLDFP_DECIMALPLATFORM_C99_TR mode.
Need to include decSingle.h (which transitively includes decDouble and decQuad) even in hardware mode, as we still need decNumber functions.
Comment out ADAM's quantum functions to avoid errors in hardware.
Reinterpret cast to const decDouble*.
Print strings for iostream unit tests.
Overload for operator<< on ValueTypeXX.
Hardware vs software cast for set(exponent, bcd, sign).
Need extern "C" to include decNumber.
Need platform-dependent printHex function.