install script: added missing quotes around variables

this makes the script fail if there is whitespace in a variable
install script: simplified php version check
install script: don't use mktemp before checking its availability
install script: fixed composer search
install script: fixed typo
Added test case for SensorInterpreter
Harmonize SQL group expression handling
Merge pull request #159 from andig/add-sensor-test

Add test case for SensorInterpreter
Fix PHP strict mode error
Merge pull request #160 from andig/add-sensor-test

Fix PHP strict mode error
Fix borked test to fake expected value
Merge pull request #161 from andig/add-sensor-test

Fix borked test to fake expected value
Remove test case that fails inconsistently across databases
Merge pull request #162 from andig/add-sensor-test

Remove test case that fails inconsistently across databases