ZynAddSubFX/FLTK: fixed detection of freetype2 include path once more

Commit 26665dde55cfa589f166998ea587db70cd516b68 was not complete as we have
to find the Freetype package and also look for freetype2 include path.
AutomatableModelView/ContextMenu: option for unlinking all controls

Integrated patch by Rodrigo Rodrigues da Silva which adds an option
to all AutomatableModelView's context menu allowing to unlink all
linked controls.
AutomatableModelView: adopted new coding style
PianoRoll: fix odd time signature issues (bugs #274 and #172 at Sourceforge)
config option to enable waveform display by default
Merge pull request #30 from softrabbit/stable-0.4

PianoRoll: fix odd time signature issues (bugs 274 and 172 at SF)
Merge pull request #31 from grejppi/stable-0.4-displaywaveform

config option to enable waveform display by default
Merge pull request #1 from LMMS/stable-0.4

pulling changes
fixed segfault in piano roll when no pattern is open
Merge pull request #33 from grejppi/stable-0.4-pianorollsegfaultfix

fixed segfault in piano roll when no pattern is open
Export dialog: Make cancelling an export work immediately
Changed "Default preset" to the actual plugin name
ZynAddSubFX/FLTK: Yet another fix for finding freetype

Revert changes of commit 17babf6abc3d5de09bbbb4e5b72248a530c47728 as commit 26665dde55cfa589f166998ea587db70cd516b68 was complete indeed regarding the FIND_PACKAGE statement.
Add REQUIRED statement to FIND_PACKAGE(Freetype)
Use FREETYPE_INCLUDE_DIRS instead of FREETYPE_INCLUDE_DIR_freetype2 or FREETYPE_INCLUDE_DIR_ft2build
Merge pull request #36 from Lukas-W/stable-0.4

ZynAddSubFX/FLTK: Yet another fix for finding freetype
Merge pull request #35 from softrabbit/stable-0.4

Make cancelling an export work immediately
Merge branch 'stable-0.4' into stable-0.4-new-fx-mixer
ZynAddSubFX/FLTK: The last freetype fix, I promise.

Using FREETYPE_INCLUDE_DIRS turned out to break the build as it is a list consisting of two paths.
During configuring, the list is then concatenated to "path1 path2". This makes cmake to think of the second path as the directory to configure.
Fixed by manually concatenating the strings with a ";" character.
Merge pull request #37 from Lukas-W/stable-0.4

ZynAddSubFX/FLTK: The last freetype fix, I promise.
Merge pull request #38 from grejppi/stable-0.4-defaultpresetnames

"Default preset" is not descriptive; change it to the actual plugin name
Merge branch 'stable-0.4' into stable-0.4-new-fx-mixer