RFR: 6549: Color flame chart based on package name

[Miroslav Wengner]

implemented ticket : https://bugs.openjdk.java.net/browse/JMC-6549
additionally:
1. fixed issue with displaying big data set in flameview
2. improved display speed

comments:  cell coloring algorithm is based on packageName hash with defined depth to avoid collisions and guarantee same stripPackageName color.
conclusion: the flameview is always displayed

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Commits:
 - c173c1cf: 6549: Color flame chart based on package name

Changes: https://git.openjdk.java.net/jmc/pull/29/files
 Webrev: https://webrevs.openjdk.java.net/jmc/29/webrev.00
  Issue: https://bugs.openjdk.java.net/browse/JMC-6549
  Stats: 162 lines in 5 files changed: 151 ins; 1 del; 10 mod
  Patch: https://git.openjdk.java.net/jmc/pull/29.diff
  Fetch: git fetch https://git.openjdk.java.net/jmc pull/29/head:pull/29

PR: https://git.openjdk.java.net/jmc/pull/29