not "64-bit launcher", since 64-bit is redundant in this case (reviewed by kb)

It's now required to use at least IDEA 2017.2.5 to work on IntelliJ IDEA project, this is needed to allow us excluding transitive dependencies in repository libraries settings (IDEA-178557).

(cherry picked from commit 68aebddd)

(cherry picked from commit a7d3a33b)

1. was leaf, now leaf: do nothing
2. was leaf, now not leaf: mark as not a leaf and reload children
3. was not leaf, now leaf: reload children for proper notifications
4. was not leaf, now not leaf: reload only loaded children

Added cucumber-core-2.0.1 and gherkin-4.1.3 libraries. Required at compile time.

Fixed issue: IDEA-179579 IntelliJ Cucumber support fails after update from Cucumber 1.2.5 (info.cukes) to 2.0.1 (io.cucumber)

regression after IDEA-CR-25484

IDEA-179073 JavaLikeIndentProvider indent miss