RFR: Initial commit of data plugin [v3]

[Alexandre Iline]

> Initial commit of data coverage JCov plugin. See the readme and tests.

Alexandre Iline has updated the pull request incrementally with one additional commit since the last revision:

  trailing whitespace

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Changes:
  - all: https://git.openjdk.java.net/jcov/pull/16/files
  - new: https://git.openjdk.java.net/jcov/pull/16/files/15258e79..0e495373

Webrevs:
 - full: https://webrevs.openjdk.java.net/?repo=jcov&pr=16&range=02
 - incr: https://webrevs.openjdk.java.net/?repo=jcov&pr=16&range=01-02

  Stats: 2 lines in 1 file changed: 0 ins; 0 del; 2 mod
  Patch: https://git.openjdk.java.net/jcov/pull/16.diff
  Fetch: git fetch https://git.openjdk.java.net/jcov pull/16/head:pull/16

PR: https://git.openjdk.java.net/jcov/pull/16