[ADD] crm_project_issue: link module to create lead from issues and issues from lead
[ADD] change the link between lead and issue. Now : transfrom a lead into a issue and modify the mail thread
[Fix] : external id not found in view
[Change] getting
[FIX] : modified according to tde's remarks
[FIX] modified with the remarks of apr
[FIX] : tde's last remark correction
Launchpad automatic translations update.
[ADD] deduplication of website images being uploaded
  
There is a deduplication in ir.attachment, but it's only for FS-stored content
*and* it only deduplicates storage not models (as there are access rights
issues involved).
  
The goal here is to always return the same attachment when a user uploads the
exact same image multiple times (because it's simpler or whatever).
  
Initially tried to use a binary field & digest(), but search() blows up
because it tries to utf-8 encode raw binary data. So use char & hexdigest
instead.
  
_compute_checksum returns None if the provided attachment data does not look
like a website image attachment.
  
Unhandled: multiple existing matches, maybe a UNIQUE constraint on the
checksum field would be a good idea just in case.

cherrypicked from saas-3's xmo@openerp.com-20140303153855-5f2l8v0jq2mgb26f
which had to be backed out (as the patch adds a new stored field)
[MERGE] [ADD] crm_project_issue module: create issues from leads.
This bridge and optional module add a button on the lead form view to
allow users to create issues from leads. The lead is distroyed during
the operation. All communication history is kept and transferred to the
new issue.