Allow insert into "Find" tool panel

Fixes a problem where the character was inserted in the last active editor instead of the focused "Find" tool panel
Second attempt to fix this package for mini editors

Found method of selecting the active editor mentioned here: https://discuss.atom.io/t/how-can-we-help-you-write-packages/4268/9
Merge pull request #2 from raphinesse/patch-1

Allow insert into "Find" tool panel