Make incremental compilation the default for all profiles.

Author: michaelwoerister

src/cargo/core/profiles.rs

@@ -406,7 +406,7 @@ impl Default for Profile {
             debug_assertions: false,
             overflow_checks: false,
             rpath: false,
-            incremental: false,
+            incremental: true,
             panic: None,
         }
     }
@@ -467,7 +467,6 @@ impl Profile {
             debuginfo: Some(2),
             debug_assertions: true,
             overflow_checks: true,
-            incremental: true,
             ..Profile::default()
         }
     }