updated OSL to 1.5, compile fixes.
Merge pull request #482 from est77/OSL_update

updated OSL to 1.5, compile fixes.
support per-control point width in temporary curve file format.
Merge branch 'master' of github.com:appleseedhq/appleseed
Parameter can have value between tags

Until now there was only the possiblity to add a value for a parameter
using the value attribute. This had the disadvantage of not allowing
the preservation of some special characters such as newlines.

The solution to this problem is to enclose the value between a pair
of tags of the same type: e.g. <parameter name="metallic">15</parameter>.

This is particularly useful in the case of disney expressions.

Signed-off-by: Marius Avram <marius.avram1309@gmail.com>
Merge pull request #484 from marius-avram/parameter_change2

Parameter can have value between tags
Fixed compile errors in debug mode
Split OIIO and OSL code paths. OIIO Texture system improvements.
Merge remote-tracking branch 'upstream/master' into est
Merge pull request #485 from est77/est

Split OIIO and OSL code paths. OIIO Texture system improvements.