added cancelation of asnyc jobs
fixed mruby action
fixed compile error
bugfix for AQL query optimiser

the following type of query was too eagerly optimised, leading to errors in code-generation:

   LET a = (FOR i IN [] RETURN i) LET b = (FOR i IN [] RETURN i) RETURN 1

the problem occurred when both lists in the subqueries were empty. In this case invalid code
was generated and the query couldn't be executed.
updated CHANGELOG
typecast
added password token functions
Merge branch '2.0' of github.com:triAGENS/ArangoDB into 2.0
added foxx app to change initial password
cleaned manifest.json
fixed path
added configuration module, documentation is not there yet
Ported the version check from devel
release version 2.0.3