Added _gradle and _gradlew as symbolic links to gradle.plugin.zsh,
otherwise the plugin was not properly loaded.
Output from `gradlew tasks --all` is now parsed in two levels,
first we find segments between `------...` and a newline.
Second, all those lines are parsed and cleaned using awk
and added to .gradletasknamecache.
Tested on gradle 2.13, and gradlew 2.14.
