fix: add in missing sourcing for bash's shell integration (#102)

Signed-off-by: Chapman Pendery <cpendery@vt.edu>

shell/shellIntegration.bash

@@ -1,3 +1,17 @@
+if [ -r ~/.bashrc ]; then
+    . ~/.bashrc
+fi
+if [ -r /etc/profile ]; then
+    . /etc/profile
+fi
+if [ -r ~/.bash_profile ]; then
+    . ~/.bash_profile
+elif [ -r ~/.bash_login ]; then
+    . ~/.bash_login
+elif [ -r ~/.profile ]; then
+    . ~/.profile
+fi
+
 __is_prompt_start() {
 	builtin printf '\e]6973;PS\a'
 }
@@ -10,7 +24,7 @@ __is_update_prompt() {
 	if [[ "$__is_custom_PS1" == "" || "$__is_custom_PS1" != "$PS1" ]]; then
         __is_original_PS1=$PS1
         __is_custom_PS1="\[$(__is_prompt_start)\]$__is_original_PS1\[$(__is_prompt_end)\]"
-        PS1="$__is_custom_PS1"
+        export PS1="$__is_custom_PS1"
     fi
 }