disable incr. comp. while testing

Author: japaric

ci/script.sh

@@ -38,6 +38,8 @@ main() {
     echo 'cortex-m = "0.4.0"' >> $td/Cargo.toml
     echo 'cortex-m-rt = "0.3.0"' >> $td/Cargo.toml
     echo 'vcell = "0.1.0"' >> $td/Cargo.toml
+    echo '[profile.dev]' >> $td/Cargo.toml
+    echo 'incremental = false' >> $td/Cargo.toml
 
     case $VENDOR in
         Atmel)