Set the request context on caught HTTP_Exceptions

When HTTP_Exceptions are caught inside of the Internal Request Client,
the current request will be set inside of the Exception using the
HTTP_Exception::request() method.

This fixes #4635
Merge pull request #316 from EvanPurkhiser/fixup/4635

Set the request context on caught HTTP_Exceptions
refs #4635
Fixes #4637: Replace iconv with mb_convert_encoding for beter support in PHP 5.4.3+
Merge pull request #363 from rjd22/3.3/bugfix/replace_iconv_with_mb_convert_encoding

Fixes #4637: Replace iconv with mb_convert_encoding for beter support in...