Tweaks and fixes

• Estimates : heavily reworked estimates under structured estimates to be easier to use / drive. Uses alot of structures / idioms from website structure
  • Re-enable drag and drop. Was accidentally removed last time this screen was modified
  • Add website structure style move buttons
  • Reorganised how estimates display in structure. Previously any estimate younger than  3 months would display in structure. Now only estimates which are created explicitly in the structured estimates screen with display here.  For non structure estimates there is a checkbox on modify to drop them into the structured list of estimates.
• Website structure. Some low level tweaks in order to reuse the code here for estimate stuff described above. Some functional improvements
  • Inactive menu options are italic / grey
  • external links are blue
  • webclass customized pages are green
  • Smarter pre-expanded tree on opening window based on # of records in the tree
• bugfix with selling parts to a deal. If deal doesn't have a customer attached to it at time parts are ordered, on receive you'll get some screwy but ignorable errors that pop on screen at time of parts receive.
• constrain default discount manipulation on customer based on login. In login setting is a new switch. Enable it to constrain access to discount settings on modify contact
  
• linkint parts image downloader refreshed
• Low level bugfixs
  • Modify value of some unit connected txn postings via business -> activity, such as rebates would throw a nullpointerexception. Now fixed
  • Receive daily order. If you exit receive daily order, c9 wants to save work so far to a local file. IF this fails for some reason, e.g. windows file permission issue, c9 would throw a nullpointerexception. Now tidied to cope better with failure to save temporary changes
  • Under some very exotic circumstances with functions like modify connected txns, c9 could throw a NullPointerException. In specific case of modify connected a precondition of triggering the bug is you re-select the txn you are connecting : a redundant step so workaround is to not do this.  Now fixed (Bug in loadByQuery() optimisation when multiple txns but only one more needs to be loaded as others are already loaded )
  • Backdating a txn with deleted lines would fail. e.g. unit purchased flipped to goods only would delete bank payment posting. Then backdating that txn will not work. Now fixed (was not correctly materializing last supply/alloc dates on deleted lines, blowing up the db check constraints )