Patch from Dimitry Sibiryakov - enable access to messages longer than 64Kb from SQLDA. Slightly modified to avoid code duplication.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59255 65644016-39b1-43b1-bf79-96bc8fe82c15
Make functions in IMessageMetadata non-const like the rest of interfaces

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59256 65644016-39b1-43b1-bf79-96bc8fe82c15
Corrected gfix messages to avoid user's panic. Reviewed by Vlad.

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59257 65644016-39b1-43b1-bf79-96bc8fe82c15
Misc

git-svn-id: svn+ssh://svn.code.sf.net/p/firebird/code/firebird/trunk@59258 65644016-39b1-43b1-bf79-96bc8fe82c15