doc: create specific uninstall sections

move recipes from "Good Things to Know"
add devscript list_recent_pkg_ids

Another way to get pkg ids -- which recent installs are most recent.
example external commands
Lynxlet 0.8.1
Merge pull request #2715 from miguelfrde/lynxlet

Lynxlet 0.8.1
Merge pull request #2681 from rolandwalker/doc_uninstall_sections

doc: create specific uninstall sections
Merge pull request #2698 from rolandwalker/ext_command_examples

example external commands
Merge pull request #2689 from rolandwalker/devscript_list_recent_pkg_ids

add devscript list_recent_pkg_ids
SourceTree 1.8.1
Merge pull request #2717 from ahbeng/sourcetree

SourceTree 1.8.1
Update Genymotion to 2.1.0