Handle split EPs, standardise series punctuation

[snejus]

Added

• album:

  • Handling unnamed (after removal of catalognum and artist names) split EPs that
    have two artists. In accordance with [title guidelines], the EP is named by separating the artists
    with a slash.

  • Following the [title guidelines], the standard series format now applies to
    Vol/Vol., Volume, Pt too. Previously we only considered Part.

    • Compilation - Volume 2
    • Compilation Volume 2 -> Compilation, Volume 2
    • If series is in the beginning of the album, it is moved to the end
      • Vol. 2 - Compilation -> Compilation, Vol 2
    • We also ensure the delimiter for abbreviations, space, and removal of leading zeroes
      • Vol02 -> Vol. 2

  • Replace (Remixes) -> Remixes

• albumtype: the EP albumtype is recognized for split EPs.

Updated

• album:

  • Remove + Some remix
    • Album + Someone's Remix

• catalognum: do not treat RD-9 (Behringer RD-9) as a catalognum

• title:

  • Remove Presented by...
    • Title [Presented by Artist]
    • Title (Presented by Artist)
  • Remove preceding number prefix when all album tracks have it and there are two numbers
    • 01 Title, Other Title
    • 1 Title, 2 Other Title
    • 01 Title, 02 Other Title.

Fixed

• All zero width space characters (\u200b) are now removed before parsing.

• album:

  • Add many cases of missing EP and LP bits when they are found in the comments
  • Fix series numbering format: when it is delimited by some character, keep it.
    Otherwise, separate it with a comma
    • Album - Part 2
    • Album Part 2 -> Album, Part 2
  • Tackled some edge cases where label name wrongly stayed on the album
    • Label: Album
    • Label - Album
  • Remove Bonus

[coveralls]

Pull Request Test Coverage Report for Build 5031680127

• 272 of 287 (94.77%) changed or added relevant lines in 4 files are covered.
• 4 unchanged lines in 2 files lost coverage.
• Overall coverage decreased (-0.9%) to 87.782%

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Changes Missing Coverage	Covered Lines	Changed/Added Lines	%
beetsplug/bandcamp/album.py	94	109	86.24%

Files with Coverage Reduction	New Missed Lines	%
beetsplug/bandcamp/init.py	1	66.15%
beetsplug/bandcamp/_metaguru.py	3	94.65%

Totals
Change from base Build 4167540772:	-0.9%
Covered Lines:	975
Relevant Lines:	1082

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💛 - Coveralls