[IMP] Cache bundles in ir.attachments instead of a LRU

Forward ported from 8.0's commit: 8402625
[FIX] mail: bad test
[IMP] hr: strenghtening of write()
[FIX] bundles: fix compiled css assets recomposition

- Do not include css in less source because malformed css will break
  less compilation
- Always recompose compiled css, even if not in debug mode
- Less and sass compilers mode @at-rules on top in order to comply
  to css 2.1, those @at-rules where left-over during the recompostion
  because they lost their marker. Those are now handled as virtual
  inline stylesheets.
[FIX] ir.attachments of compiled css assets not properly invalidated
Update __openerp__.py

Little mistake in the descreption seen during translation.
[FIX] website.theme: when the user does not raise an exception. Display error message when the user install or customize a theme.
[FIX] tour: don't display all log when log an error
Merge pull request #1875 from ma78nee/patch-1

Little description mistake
Merge pull request #1781 from odoo-dev/master-fix-theme-need-alltime-less-chm

[FIX] website.theme: when the user does not raise an exception.
[FIX] Do not assume all exceptions with a code attribute to be HTTPExceptions
[IMP] Rename Schedule/log Call button
[IMP] website snippet new option, gallery

website.snippet: The methods described in javascript will be called automatically from the data-method_name = value on li snippets options. The methods are called in the order relative to children of xml (eg: <li data-method1=value1> ... <li data-method2=value2> ... </ li>, the method1 is then called method2). Methods receive two arguments: type (over, click, reset) and value. data-snippet-id-option becomes data-snippet-id. Several xml options can use the same data-snippet-id.

add a new gallery snippet

convert website_sale to the new option system
[IMP] Use radio widget in various views

+ some UI messages improvements

(Closes #1913)
[IMP] website.theme: add button in customize theme modal to show all theme modules
[IMP] mrp: allow disassembling through MO