increment version

Former-commit-id: bb3e4b64601ab362672955a81ef15bef1f80122a

RELEASE_HISTORY.txt

@@ -1,2 +1,3 @@
+0.1.8  Embree and xml (windows only) extras
 0.1.5  Compilation on windows, bug fix for compilation with cygwin
 0.1.1  Alpha release with core functions, extras, examples

VERSION.txt

@@ -3,4 +3,4 @@
 # Anyone may increment Minor to indicate a small change.
 # Major indicates a large change or large number of changes (upload to website)
 # World indicates a substantial change or release
-0.1.7
+0.1.8