Check at configure time if CPU supports the requested SIMD optimization

.gitignore

@@ -5,6 +5,7 @@
 *.obj
 *~
 errs
+*#
 
 # Precompiled Headers
 *.gch
@@ -48,3 +49,33 @@ config.status
 /stamp-h1
 /config.sub
 /config.guess
+
+
+# Packages #
+############
+# it's better to unpack these files and commit the raw source
+# git has its own built in compression methods
+*.7z
+*.dmg
+*.gz
+*.iso
+*.jar
+*.rar
+*.tar
+*.zip
+ 
+# Logs and databases #
+######################
+*.log
+*.sql
+*.sqlite
+ 
+# OS generated files #
+######################
+.DS_Store
+.DS_Store?
+._*
+.Spotlight-V100
+.Trashes
+ehthumbs.db
+Thumbs.db