Upgrade to Ext JS 3.4.0.

* extjs: remove unneeded files.
app_home: use extjs for paging store.

* js.all: add global variable for page size.
rca_lap_severity: use paging.
app_adm_user: use internal paging store and toolbar.

* rca_lap_severity: fix query's start and limit.
trn_lap: use json store and internal paging toolbar.
Remove Ext.ux.PagingStore.