Implement character string music notation for sequences

[Dario Seminara]

Desirable features:

• Espatial-temporal relation, for example four characters equal one beat, flexible according user needs
• Notes are named CDEFGAB and can be altered using # and b and the octave number. So
  F
  F#
  F#4
  F 4
  ...Are all valid notes

Capital letters should act as separators and spaces are silence, example
"A B C=F#4FFF"
It plays:
A semiquaver,
silence semiquaver
B semiquaver
silence semiquaver
C quaver
F# octave 4 quaver + semiquaver duration note
and finally three F semiquavers

REmember on any situation the duration of the note is proportional to the lenght of the notation on character string plus the = extension

• Insert of any playable object using aliases, for example
  seq("ABCDXAAAX", {X: snareSound});
• Key Signature allowing alteration of any note, notes can be de-altered on notation using dash, example:

"F=F=F-F-"
It should play two sustained F and then two unaltered F

[Dario Seminara]

Done, except for aliases, that and any other improvement not described on this issue will be covered on other issues