RFR: Add tabfiles to jcheck configuration [v2]

[Magnus Ihse Bursie]

> The tabfiles setting is just like the files setting, but it lists files in which tabs are allowed.
> 
> (This is to support makefiles)

Magnus Ihse Bursie has updated the pull request incrementally with one additional commit since the last revision:

  Disallow trailing tabs even for tabfiles

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Changes:
  - all: https://git.openjdk.java.net/skara/pull/929/files
  - new: https://git.openjdk.java.net/skara/pull/929/files/b4ffcde1..d8c4f75d

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=skara&pr=929&range=01
 - incr: https://webrevs.openjdk.java.net/?repo=skara&pr=929&range=00-01

  Stats: 4 lines in 1 file changed: 1 ins; 0 del; 3 mod
  Patch: https://git.openjdk.java.net/skara/pull/929.diff
  Fetch: git fetch https://git.openjdk.java.net/skara pull/929/head:pull/929

PR: https://git.openjdk.java.net/skara/pull/929