Free-text search source code

[bewee]

As a developer using Algernon, I would like to search the whole source code for occurences of a given string, in order to gain quicker access to this built-in feature.

Acceptance Criteria

• Make free-text search of Squeak accessible through Algernon (just like ALT+Shift+E does)
• Add keyword search
• Open popup on search
• Do it similar to the existing evaluate feature

[TheGrayStone]

One could look into whether it is possible to show the results directly in the result list (e.g. via tabbing into an entry named Show results for this search - similar to how evaluate works).