Cleanup Bash scripts.

This makes them pass shellcheck. Except for a few unused
export warnings.

I also wonder if the majority of these files should be
in the root of the project, or should be moved to "build-scripts"
(or should still even exist).

a few minor changes

one more minor changes

merge-dev-to-master.sh

@@ -1,7 +1,7 @@
 #!/usr/bin/env bash
-curbranch=`git branch | grep \* | cut -d ' ' -f 2`
+curbranch=$(git branch --show-current)
 
-if [[ x"$curbranch" == x"master" || x"$curbranch" == x"develop" ]]; then
+if [[ "${curbranch}" == "master" || "${curbranch}" == "develop" ]]; then
     rm -f include/build_timestamp.h
     git checkout include/build_timestamp.h