[FIX] qweb: css minified in multiple page for IE

On internet explorer 6, 7, 8 and 9, the limit of CSS rules in a stylesheet is
4095 (http://blogs.msdn.com/b/ieinternals/archive/2011/05/14/10164546.aspx).

This commit breaks down a CSS bundle in several pages for these IE versions.

To do this, the CSS tag added is of the kind : /web/css.0/{xmlid}/{version} in
which there is:

- the whole CSS if there is no more than one page,
- a list of @import pointing to the multiple pages.

note: if a modification lowers the number of page, an old page may stay in
ir_attachment (e.g: go from 4 to 3 pages, the old 4th page of another version
will not be deleted untill the number goes again up to 4).

Note: the method css(self) previously returned an unicode variable (the first
time) or an str variable (the following times, if already cached), the fix
also correct this so an str variable is always returned.

fixes #5050

opw-627116

0 files changed, 0 insertions, 0 deletions