another safe guard when adding our instruction. closes #79

refacored tests to use StructTest as base class

this makes schema setup and data loading much easier and gets rid of a
lot of duplicate code

catch JSON error in importer

added testing for tag autocompletion #80

new base type for testing

introduces helper functions and basic setup. needs to be introduced to
all the tests, yet.

the column array should start at 0 and be sorted correctly

For some reason we stored them in column ref order. This might break
things that are not covered by tests but I hope not.

run custom query for tag autocompletion #80

removed distinct feature from search

this was added for tag autocompletion but does not work as expected.
should be implemented in tag type directly

catch fatal errors in AJAX responses

autocomplete: print stack trace to console if allowdebug

fix caching behaviour with dynamic parameters. closes #78

check for page existance in search. fixes #77

This requires an uptodate sqlite plugin

do not clear data on delete during move #72

fix error when an aggregation tries to select a nonexisting column

print stacktrace on allow debug

adjust cachung if an aggregation depends on dynamic values #75

fixed struct filter vars and added tests #75

JSON_PRETTY_PRINT is not available in PHP 5.3

build returns an int

added json import/export tests

the json facilities can now be used for other tests as well

added Schema Import #32

This also adds a nice interface for that to the schema editor

fixed enabled/disabled handling in JS

allow exposting struct schemas as JSON #32

support for dynamic filter place holders #75

tests for struct stuff still missing
no cache handling, yet

avoid errors when no schema or column is given