Add version number auto-increment support.

'git flow hotfix start' and 'git flow release start' will suggest
a new version number based on previous tags in the respository.
The respective stop commands will suggest the same version number.
Version numbers are in the form [major].[minor].[revision]
(eg. 1.3.5). 'hotfix' assumes a revision bump and 'release' assumes
a minor bump, but suggestion can be overridden. In addition
'git flow hotfix start 1.0.0' and 'git flow release start 1.0.0'
still work as expected.

git-flow-hotfix

@@ -130,9 +130,11 @@ parse_args() {
 
 require_version_arg() {
 	if [ "$VERSION" = "" ]; then
-		warn "Missing argument <version>"
-		usage
-		exit 1
+    default_suggestion="$(git_next_revision_version)"
+		printf "Version number for this hotfix: [$default_suggestion] "
+		read answer
+		VERSION=${answer:-$default_suggestion}
+    BRANCH=$PREFIX$VERSION
 	fi
 }
 

git-flow-release

@@ -127,9 +127,11 @@ parse_args() {
 
 require_version_arg() {
 	if [ "$VERSION" = "" ]; then
-		warn "Missing argument <version>"
-		usage
-		exit 1
+    default_suggestion="$(git_next_minor_version)"
+		printf "Version number for this release: [$default_suggestion] "
+		read answer
+		VERSION=${answer:-$default_suggestion}
+    BRANCH=$PREFIX$VERSION
 	fi
 }
 

gitflow-common

@@ -105,6 +105,7 @@ git_tag_exists() {
 	has $1 $(git_all_tags)
 }
 
+
 #
 # git_compare_branches()
 #
@@ -312,3 +313,56 @@ require_branches_equal() {
 		fi
 	fi
 }
+
+#
+# Functions for auto version incrementing
+#
+
+git_current_version() {
+  echo "$(git_all_tags)" | grep -e '.*[0-9]*\.[0-9]*\.[0-9].*' | sed '$!d' | sed -n 's/[^0-9]*\([0-9]*.[0-9]*.[0-9]\)/\1/p'
+}
+
+git_current_major_version() {
+  echo "$(git_current_version)" | sed -n 's/\([0-9]*\).[0-9]*.[0-9]*/\1/p'
+}
+
+git_current_minor_version() {
+  echo "$(git_current_version)" | sed -n 's/[0-9]*.\([0-9]*\).[0-9]*/\1/p'
+}
+
+git_current_revision_version() {
+  echo "$(git_current_version)" | sed -n 's/[0-9]*.[0-9]*.\([0-9]*\)/\1/p'
+}
+
+git_next_major_version() {
+  if [ $(git_current_version) == ""]; then
+    echo "1.0.0"
+  else
+    maj=$( echo "$(git_current_major_version)" | awk '{ print $1 + 1 }' )
+    min=0
+    rev=0
+    echo "$maj.$min.$rev"
+  fi
+}
+
+git_next_minor_version() {
+  if [ $(git_current_version) == ""]; then
+    echo "1.0.0"
+  else
+    maj=$(git_current_major_version)
+    min=$( echo "$(git_current_minor_version)" | awk '{ print $1 + 1 }' )
+    rev=0
+    echo "$maj.$min.$rev"
+  fi
+}
+
+git_next_revision_version() {
+  if [ $(git_current_version) == "" ]; then
+    echo "1.0.0"
+  else
+    maj=$(git_current_major_version)
+    min=$(git_current_minor_version)
+    rev=$( echo "$(git_current_revision_version)" | awk '{ print $1 + 1 }' )
+    echo "$maj.$min.$rev"
+  fi
+}