squashed: modules, parsing functions, makernotes

- renamed file exiftool.js to main.js (for upcoming browser AMD support)

- made it more modular:
    - main.js is just the logic,
    - exif.js is content for EXIF with TIFF, GPS and IPTC
    - makernotes.js is the switch for requiring makernotes
    - each file in the makernote folder is content for a specific
makernote
    - redaktor.meta.iptc and redaktor.meta.xmp parser can be attached
or contributed (plug&play)

- parsing (explaining) functions for EXIF, Image/TIFF and GPS core
    - :: "core tags" should now have about 99% coverage and 99%
compliance

- parsing (explaining) functions for makernotes of the vendors:
Agfa, Canon, Casio, Epson, Fujifilm, Kodak (stub), Minolta, Panasonic,
Leica, Pentax (stub), Ricoh, Sanyo, Sigma, Sony
    - :: "makernote tags" should have about 42% coverage and 95%
compliance
    "Man who catch fly with chopstick accomplish anything" ;)

- new reports
    - compares exiftool.js just against the perl reference (other
projects are to weak) but allows sorting and generates
    a) compliance report (which results from .js are similar and which
are not)
    b) coverage report (which tags/results from perl are
covered/similar and which are not)

- different minor changes, see comments like
// TODO
// FIXME
// NOTE

[SL]