AbstractBuildForm.php: Removed some unused comments. Bug fix: do htmlspecialchar_decode() always when FE_ENCODE is set to encodeSpecialchar.
QuickFormQuery.php: mv necessary systemStoreUpdate() closer to instantiating of classs Store.

Store.php: change function getNonSystemSipParam() from private to public
AbstractBuildForm.php, BuildFormBootstrap.php, BuildFormTable.php: use of getNonSystemSipParam() in deriveNewRecordUrlFromExistingSip() and createDeleteUrl()..

Manual.rst: Doc update for periodId.
DatabaseUpdateData.php, formEditor.sql: Table 'Period' and sample record.
Store.php: Implement systemStoreUpdate()
QuickFormQuery.php: call to store->systemStoreUpdate() - might solved in a better way..

Dirty.php: workaround for #4127

# Conflicts:
#	extension/qfq/qfq/store/Sip.php
#	tests/selenium/testInputModeSwitcher.js
#	tests/selenium/testTypeAhead.js

Save.php: replace constant

Makefile: fixed unwanted removing of whole 'doc' by 'maintainer-clean' - doc nowadays contains QFQ related manually created documentation.

Makefile: change installation of phpDocumentor to --alldeps and remove 'phpdoc/'.

Dirty.php: save 'expire' value.

DatabaseUpdateData.php: Table Form: recordLockTimeoutSeconds - default changed from 0 to 900 secs. Existing forms get the default timeout timout interval.
Dirty.php, QuickFormQuery.php: recordLockTimeoutSeconds will be retrieved from the Form.recordLockTimeoutSeconds definition (instead of parsing config.qfq.ini). Therefore a definition per form ist possible.

# Conflicts:
#	extension/qfq/qfq/Constants.php
#	extension/qfq/qfq/form/Dirty.php

Dirty.php: add comments. Add timeout checking

file.php, load.php, Html2Pdf.php: minor updates.
Dirty.php, QuickFormQuery.php: optional $lockTimeout as parameter during instantiating. Return $lockTimeout where necessary. Otherwise read qfq.config.ini. Refactor process(), acquireDirty(), checkDirtyAndRelease().