small bugfixes and refactoring for lexical_cast

[Antony Polukhin]

lexical_cast requires refactoring:

• reduce templates count
• leave only one lexical converting class (at least for modern compilers)
• fix small TODOs and XXXs from source code
• make lexical_stream_limited_src more readable
• update status/explicit-failures-markup.xml

small bugs to fix:

• make lexical_cast_inf_nan_test.cpp pass on Itanium pltform
• make lexical_cast able to convert signed and unsigned chars to wchar_t and update lexical_cast_wchars_test

[Antony Polukhin]

(In [73313]) Fixes #5732.

• reduces templates count
• leaves only one lexical converting class (at least for modern compilers)
• fixes small TODOs and XXXs from source code
• makes lexical_stream_limited_src more readable
• updates status/explicit-failures-markup.xml
• makes lexical_cast_inf_nan_test.cpp pass on Itanium pltform
• makes lexical_cast able to convert signed and unsigned chars to wchar_t and updates lexical_cast_wchars_test

[Antony Polukhin]

(In [73323]) Fixes #5732.

• fixes performance regression, that was added by previous commit
• fixes float types preformance regression for old compilers

[Antony Polukhin]

(In [73328]) Fixes #5732.

• fixes some warnings and bugs for VC

[Jürgen Hunold]

testcase for std::vector<char>

[Jürgen Hunold]

the last patches broke some of my code which uses lexical_cast to parse values from std::vector<char>

Something as simple as

std::vector<char> buffer; return boost::lexical_cast<int>(&buffer[0]);

fails with

BOOST_ROOT/boost/lexical_cast.hpp:1091:43: error: no matching constructor for initialization of 'std::basic_ostream<char>'

std::basic_ostream<CharT> stream(&stringbuffer);

^~

this is the start of the clang diagnostic.

Both gcc (Ubuntu 4.6.0-3~ppa1) 4.6.1 20110409 (prerelease) and clang version 3.0 (trunk 135897)

output contained in attached testcase lex.tar.gz

[Antony Polukhin]

(In [73357]) Fixes #5732.

• fixes compilation errors for nonconst char arrays

[Antony Polukhin]

Replying to jhunold:

the last patches broke some of my code which uses lexical_cast to parse values from std::vector<char>

Fixed in [73357]. Added some test cases. Thanks again for the testing.

[Antony Polukhin]

(In [73384]) Fixes #5732.

• fixes compilation errors pgi compiler
• fixes some bugs for MinGW compiler

[Antony Polukhin]

(In [73401]) Fixes #5732.

• one more try to fix compilation errors on pgi compiler

[Antony Polukhin]

(In [73435]) Fixes #5732.

• one more try to fix compilation errors on pgi compiler

[Antony Polukhin]

(In [73446]) Fixes #5732.

• at least compiles on pgi

[Antony Polukhin]

(In [73601]) Fixes #5732.

• some fixes for WinCE
• updated explicit failures markup

[Antony Polukhin]

(In [73640]) Fixes #5732.

• suppress compilation warnings, if the compiler requires a return, even when it can never be reached