Add learn lisp hard way
Add PowerShell Succinctly book.
Add link to PDF and Kindle for Android Succinctly

Added direct link to PDF and Kindle formats at syncfusion.com;
No login required.
Merge pull request #1062 from luis-puhl/master

Add link to PDF and Kindle for Android Succinctly
Merge pull request #1060 from levibostian/powershell-succinctly

Add PowerShell Succinctly book.
Merge pull request #1056 from vishalsodani/master

Add learn lisp the hard way book
27,000
add "The Python GTK+ 3 Tutorial"
Merge pull request #1064 from taurenchieftain/master

add "The Python GTK+ 3 Tutorial"
Fix formatting
Merge pull request #1066 from uschek/master

Fix formatting
Update CONTRIBUTING.md