Update to installation.md for Windows users

An overhaul of the section "Windows note on Java, Ant and Android". Fixed link for Ant. Reorganized under headings.  Included note about installing Android SDK and PATH variables for tools and platform-tools.
Update to installation.md for Windows users

An overhaul of the section "Windows note on Java, Ant and Android". Fixed link for Ant. Reorganized under headings.  Included note about installing Android SDK and PATH variables for tools and platform-tools.
Merge pull request #186 from jawinn/patch-1

Update to installation.md for Windows users