apply constraints to names for tasks and task instances in resource configuration

The same rules as for IEC identifiers are applied.
- no non-lating characters, ...
- no IEC keywords
- check for duplicate names in resource configuration

closes #19

.project

.directory

syntax: regexp
^tests/.*/build$
^.idea/.*
syntax: regexp
^.*\.pyc$
syntax: regexp
^.*~$
syntax: regexp
^.*\.swp$

bug_report.*\.txt
i18n/.*.new$
revision