Version 0.7 (#149)

Since it will likely be a while before we can release 1.0, how about a 0.7 release? I'm bumping the minor version because it is breaking (`scaledual`, and the improved accuracy of conversions).

Author: timholy

Project.toml

@@ -1,6 +1,6 @@
 name = "FixedPointNumbers"
 uuid = "53c48c17-4a7d-5ca2-90c5-79b7896eea93"
-version = "0.6.1"
+version = "0.7.0"
 
 [compat]
 julia = "1"