Merge branch 'develop'
[#43] first implementation of cascading questions

* reads cascadeNodes from GAE using remote API
* puts the nodes in a sqlite database
* uploads the file to S3
Merge branch 'develop' into feature/43-cascading-questions

Conflicts:
	src/akvo/flow_services/core.clj
[#43] Parens formatting, no major changes
[#43] Refactor code trying to isolate data transformation

* normalize-ids works with just a sequence of nodes
* get-nodes only makes the data fetch in batches and returns the nodes
  sorted by `:id`
[#43] WIP - refactor code to use :id :name :parent convention

* Create the database with unique index on (name, parent)
* Add debug logging
[#43] Adds some error handling and logging
[#43] Corrects :import statement
[#43] Use hash of request params as id

* Updates project version
[#43] Format core namespace declaration
[#43] Incorporate changes based on feedback by @jonase

* Fixes issue reading POST body
[#43] Remove the password from the DEBUG logs
[#43] Add some more INFO logging
[#43] Use defonce for atoms

* defonce will only define a Var if is not bound to a value. Running the
  service and compiling a file (e.g. via Emacs) makes the config atoms
  to be resetted
Merge pull request #53 from akvo/feature/43-cascading-questions

Feature/43 cascading questions