as requested/discussed in PR #4989, by using size_t or at least
unsigned instead of casting to int when using the size() method of stl
containers (vectors etc.) in for loops.
Doesn't work everywhere though, not without either adding more casts
elsewhere or with massive code changes or with different compiler(s')
warnings.
Tested with MinGW 64-bit, MinGW 32-bit and MSVC 64-bit.
- tick names a position on the time axis
- tick is always a Fraction()
- only Measure() and Segment() (and Tuplet?) have a tick value
- tick() for an generic element return only a sensible value if isMeasure() or isSegment() or isSegment(parent())
- "ticks" names a duration stored in a Fraction()
- the tick value for an Segment is relative to its measure
- rename "duration" to "ticks"
- rename afrac() to tick()
- rename rfrac() to rtick()
- rename some variables, changing "fraction" into "tick"
(example: actualFraction() into actualTicks())
- Lyrics ticks are written as Fraction, on read if xmlreader sees a "/" it reads a fraction
else midi ticks for backwards compatibility
