Updated Vlad's patches for Firebird and added changes for linux

[FociNotes]

Updated Vlad's patches for Firebird support to last master and added changes for linux

1. Updated patches by Vlad Khorsun for connect to Firebird natively (http://web.firebirdsql.org/download/sphinx/2.2.11/) to the last master (Sphinx 2.3.2-beta, latest commit f9745e3 on 23 Nov 2016);
2. Add realization of CSphSource_FBSQL::SqlColumnLength method in src/sphinx.cpp - rather it simply returns 0, so indexer of the last version of Sphinx can't correctly build an index;
3. Add my own patches to all needed files (including files patched by Vlad) to compile Sphinx with Firebird support under linux (with all available configure options - --with-firebird, --with-static-firebird, --with-firebird-includes, --with-firebird-libs).

With all this changes you can easily make a linux build of Sphinx with Firebird support:
git clone https://github.com/FociNotes/sphinx.git
cd sphinx
./configure --prefix=/usr/local/sphinx --without-mysql --with-firebird
make
make install (or checkinstall to build a debian package).