Enables pasting FiguredBass elements.

To be sure the element is pasted into the right track, the track is set again after reading the element.
This also affects Dynamic, Symbol, FretDiagram, Marker, Jump, Image, Text, StaffText, TempoText.
Merge pull request #236 from mgavioli/Figured_bass_enable_copy

FiguredBass: Enables pasting FiguredBass elements.
loose CMake minimum version requirement
clean Makefile.mingw a bit
travis-ci: install cmake from ubuntu repository
travis-ci: install and use gcc 4.7
travis-ci: install g++4.7 non interactively...
travis-ci: limit number of CPUs used during compilation
TAB: make "Stem through staves" option more similar to regular pitch layout.
Merge pull request #245 from mgavioli/TAB_stems_through_staves

TAB: Stems through staves option
travis-ci: fix multi cpus build
TAB: do not draw stem portions between notes.

Also stop the stem a little before reaching the first note.
Merge pull request #249 from mgavioli/TAB_no_stems_between_notes

TAB: No stems between notes
Time Signatures: on staves with an odd number of spaces, do not leave an empty space between numerator and denominator.
inspector tweaking
fix inspector geometry management
Merge pull request #250 from mgavioli/TimeSig_on_even_lined_staves

Time Signatures in staves with even number of lines
Fix 20405: in TAB's, small notes collide with staff lines.
Merge pull request #251 from mgavioli/Fix_20405_TAB_small_notes

Fix 20405: in TAB's, small notes collide with staff lines.
TAB: the length of beam partial segments was wrong (too long for down-stems and too short for up-stems)