Merge branch 'hotfix/error-fix'
Merge branch 'release/0.4.1'
Merge branch 'release/0.5'
Merge branch 'develop'

* develop: (28 commits)
  Adds options to display connection, database and driver in dbgraph.
  Adds the Database Executer.
  Adds the ability to filter null values (column=null -> column is null, column!=null -> column is not null). Potential semantic clash with an actual value 'null'...
  Write a nice error message.
  Adds tests for grapher and exporter as well.
  Adds new testcase.
  Fixes working with BLOBs.
  Fixes encoding error in unicode arguments.
  Force displaying the whole error message.
  Refactors tests.
  Fixes include and exclude with breadth first search.
  Updates table of contents.
  Adds a table of contents
  Adds the usage of dbnav, dbgraph and dbexport.
  Fixes missing re import. Updates README.md.
  Adds an error recovery format for the writer.
  Simplifies writers.
  Uses deque as data structure.
  Adds recursive graph creation (using a breadth first search algorithm). Adds graphviz output format. Adds an option to additionally display non foreign key columns. Removes deprecated debug messages. Adds a new operator not equals (!=).
  Refactors code.
  ...
Merge branch 'release/0.6'
Merge branch 'release/0.7'
Merge branch 'release/0.8'
Merge branch 'release/0.9'
Adds new version to README.
Adds the in operator (colon in URIs) -> user@host/db/table?id:1,2,3,4 .
Removes duplicates from exported items.
Adds the option to name the table in dbexec.
Merge branch 'master' into develop

* master:
  Adds the option to name the table in dbexec.
  Removes duplicates from exported items.
  Adds the in operator (colon in URIs) -> user@host/db/table?id:1,2,3,4 .
  Adds new version to README.
Fixes exception with unknown dictionary keys.
Bumps version to 0.9.1.
Merge branch 'release/0.9.1' into develop