Add emulation of the FT2 pattern loop bug.

One of the most (in)famous FT2 bugs is the E60 bug: When E60 is used on
a pattern row x, the following pattern also starts from row x instead of
the beginning of the pattern. This can be avoided by placing a D00
pattern break on the last row of the pattern where E60 was used.

Described here: http://www.milkytracker.org/docs/MilkyTracker.html#fxE6x

Test tune:
http://api.modarchive.org/downloads.php?moduleid=55647#roadblas.xm
Merge pull request #21 from eltoder/ft2-pattern-loop-bug

Add emulation of the FT2 pattern loop bug.
adjust missing NO_PACKING and MODPLUG_NO_FILESAVE ifdefs:
CSoundFile::PackSample() and CSoundFile::CanPackSample() are only
used when writing samples and only when NO_PACKING is not defined.
sample write, in turn, is only available when MODPLUG_NO_FILESAVE
is not defined. therefore, wrap them with MODPLUG_NO_PACKING and
NO_FILESAVE ifdefs in sndfile.h, and move the MODPLUG_NO_PACKING
ifdef in sndfile.cpp to cover PackSample() and CanPackSample() too.
This doesn't affect the C-only interface, however CSoundFile class
in the C++ interface is changed, therefore MODPLUG_LIBRARY_VERSION
in configure.ac would _probably_ need changing before a release.
S3MSaveConvert and ModSaveCommand are only used when MODPLUG_NO_FILESAVE isn't defined. GetBestSaveFormat and GetSaveFormats are only meaningful when MODPLUG_NO_FILESAVE isn't defined.
disable loading midi formats. disable loading wav format.