[FIX] purchase: Do not allow to delete a purchase order line which is validated

This restriction behavior copied from the sale.order model
Moreover, the purchase.order lines state were not set to cancel when the purchase order was cancelled.
This is now the case, this behavior is also coped from the sale.order model
When the purchase order is reset to draft, we also reset the order lines state to draft
[FIX] replace .bzrignore by .gitignore, as we are now working with git
Fix detection of MIME type in message_parse()

Be careful, content-type may contain tricky content like in the
following example so test the MIME type with startswith()

Content-Type: multipart/related;
  boundary="_004_3f1e4da175f349248b8d43cdeb9866f1AMSPR06MB343eurprd06pro_";
  type="text/html"
[FIX] base: security, group settings is authorized to alter ir.config_parameter
[FIX] base: security, do not override basic ir_config_paramter ACL
Merge pull request #286 from jbq/bugfix

[FIX] mail: detection of MIME type

When parsing the mail headers, the content-type may has a 'type' attribute for Multipart/Related  objects (rfc2387).
Previous check would match on attached files of type text instead of real `content-type: text/`.
[FIX] calendar: avoid double popup, opw 606297

Some browsers (e.g. chrome) trigger onEmptyClick as well as
onBeforeLightbox during drag&drop which calls two slow_create
calls (and two popups). Workaround to kill the second one.
Merge remote-tracking branch 'odoo/7.0' into 7.0-opw-607782-dhr