Line Numbers in Slow Warnings thanks to Javassist (Eclipse only).

Here is a proposal to enhance slow warnings by adding the line number to place the marker.
This feature is available in Eclipse only.

The main issue is to find the line number from a method name. This information is missing in a .class, but we can find the line number of an opcode (opcodes are indexed in the method scope) with Javassist reflection.

A code review and comments will be appreciated, so please, don't merge it as-it :)
This is more a Request For Comments than a Pull Request.

Fred