DebuggerClient: workaround for string truncation

Fixed bug where getResourceTree was crashing when argv[1] contained
path longer than approx. 70 characters.

Problem was solved by working around the string truncation issue in
V8 debugger protocol, where strings longer than 80 characters were
always truncated.
List unit-test files on session start.

Modified implementation of ScriptFileStorage.findAllApplicationFiles()
to include all source files in the directory where the debugged application
is running.

This change allows users to set breakpoints in their unit-test files when
debugging e.g. mocha tests: `mocha --debug-brk ./test/*.test.js`.