Allow for multiline opt description in __usage. Fixes #7

test/fixture/main-usage-defaults.exitcode

@@ -0,0 +1 @@
+0

test/fixture/main-usage-defaults.stdio

@@ -0,0 +1,7 @@
+ACCPTST:STDIO_REPLACE_DATETIMES
+{datetime} UTC [     info] arg_1: 0
+{datetime} UTC [     info] arg_2: 0
+{datetime} UTC [     info] arg_3: THREE
+{datetime} UTC [     info] arg_4: FOUR
+{datetime} UTC [     info] arg_5: OOOPS
+{datetime} UTC [     info] arg_6: 

test/scenario/main-usage-defaults/run.sh

@@ -0,0 +1,33 @@
+#!/usr/bin/env bash
+set -o pipefail
+set -o errexit
+set -o nounset
+# set -o xtrace
+
+# Set magic variables for current FILE & DIR
+__dir="$(cd "$(dirname "${BASH_SOURCE[0]}")" && pwd)"
+__file="${__dir}/$(basename "${BASH_SOURCE[0]}")"
+__base="$(basename ${__file} .sh)"
+__root="$(cd "$(dirname $(dirname $(dirname "${__dir}")))" && pwd)"
+
+# Set __usage and source main.sh
+read -r -d '' __usage <<-'EOF' || true # exits non-zero when EOF encountered
+  -1 --one         Do one thing. Default="ONE"
+                   More description.
+  -2 --two         Do two things.
+                   More description. Default="TWO"
+  -3 --three [arg] Do three things. Default="THREE"
+                   More description.
+  -4 --four  [arg] Do four things.
+                   More description. Default="FOUR"
+  -5 --five  [arg] Do five things. Default="FIVE"
+                   More description. Default="OOOPS"
+  -6 --six   [arg] Do six things.
+                   More description.
+EOF
+
+echo "ACCPTST:STDIO_REPLACE_DATETIMES"
+
+source "${__root}/main.sh"
+
+for argument in ${!arg_*}; do info "${argument}: ${!argument}"; done