Update submodule quickfixsigns a1efa3f...ec7c08f

* quickfixsigns a1efa3f...ec7c08f (25):
  > quickfixsigns_register is script-local; FIX #47: Use g:quickfixsigns_lists to toggle state
  > docs
  > :QuickfixsignsSet: Takes sign classes as optional arguments
  > docs
  > doc: fix grammar/typos with "Adding new sign classes"
  > docs
  > docs
  > misc
  > misc
  > g:quickfixsigns_class_vcsdiff: Remove FocusGained event Caused infinite loop when calling git etc.
  > misc
  > Call s:UpdateLineNumbers() only when the list has actually changed
  > version
  > Add -bar to command definitions
  > g:quickfixsigns_class_vcsdiff: Update on FocusGained events
  > g:quickfixsign_use_dummy defaults to 1
  > Set the dummy sign ID correctly
  > Make sure to use new IDs for dummy signs
  > g:quickfixsign_use_dummy: Option to set dummy sign (fix #44)
  > Call s:UpdateLineNumbers() only if necessary
  > docs
  > Minor improvements to avoid unnecessary updates (fix #43)
  > g:quickfixsigns_blacklist_buffer matches full filename (don't check buffers with empty filenames)
  > Remove InsertChange from g:quickfixsigns_events
  > Configurable g:quickfixsign_timeout (default value for timeout option)