add field parent_id in tasks

for sub-task feature
sub-task feature

updated current working version
this is all so far, but more to come
add field sibling_order in tasks

for later use
preset columns/fields for tasklist

include parent
made some small fixes around missing logo and version will be 1.0 instead of 1.0.0
Sub-Task / Super-Task

renamed for clarification and distinction:
- "parent" to "super"
- "child" to "sub"
added theme "CleanFS_wSubTs", restored theme "CleanFS" to default
rename "parent_task" to "supertask"
cleanup & fix

rename "parent" to "supertask"
rename "child" to subtask"
delete *.bak files
Change split to explode.
Merge pull request #3 from xezzus/master

Fix error deprecated: function split() is deprecated
Add support for an intro message for "all projects"
add a checkbox to choose whether to display main intro message, also providing Chinese support
remove a useless default intro message
set default sort criterion to priority instead of severity
History tab now includes gravatars.
Assigned To is now including names with Gravatars.
Assigned To is seperated with a <hr> tag to make it look better.
Opened By includes a small gravatar.
Last Edited by includes a gravatar.
Due Date now includes Days Left, changes to red bold font when its 5 days left and under.
checks to see if there is a due date assigned so it wont show if its undecided.
added more conditions for the due date, days left.
When displaying a user, don't need to show their username -- the gravatar and display name are enough. Also moved Bluey theme to deprecated folder
merging in code from magicfinder
fixed small bug on undefined lang code