[O] taskjuggler exporter ignores SCHEDULED attribute and requires a space between BLOCKER tasks

[Anakreontas Mentis]

The attached file demonstrates two bugs regarding the task juggler
exporter. I load the ox-taskjuggler file and export with the key
sequence C-c C-e J j

1. SCHEDULED date is not exported as a start attribute.
2. The BLOCKER attribute requires a space between two dependency
tasks. For example, Task 3 in the attached file depends on Task 1 and
Task 2. Setting :BLOCKER:  aa,bb has no impact on the generated
file. The attribute is ignored. If I set :BLOCKER:  aa, bb (note the
space between aa and bb), the produced file declares the dependency.

* Project A                                             :taskjuggler_project:  
    :PROPERTIES:
    :leaves_holiday: "Ascension Day" 2014-05-29
    :leaves_holiday: "Whit Monday" 2014-06-9
    :leaves_holiday: "Bastille Day" 2014-07-14
    :leaves_holiday: "Assumption of Mary" 2014-08-15
    :leaves_holiday: "Armistice Day" 2014-11-11
    :leaves_holiday: "Christmas Eve" 2014-12-24
    :leaves_holiday: "Christmas Day" 2014-12-25
    :leaves_holiday: "St Stephen's Day" 2014-12-26
    :leaves_holiday: "New Year's Eve" 2014-12-31
    :start: 2014-05-05
    :END:
*** TODO Task 1
    SCHEDULED: <2014-06-18 Wed>
    :PROPERTIES:
    :start: 2014-06-18
    :Effort:   1w
    :allocate: dev
    :task_id: aa
    :BLOCKER:  previous-sibling
    # :start: 2014-05-30
    :END:
*** TODO Task 2
    SCHEDULED: <2014-06-20 Fri>
    :PROPERTIES:
    :Effort:   1w
    :allocate: dev
    :task_id: bb
    :BLOCKER:  previous-sibling
    # :start: 2014-05-30
    :END:
*** TODO Task 3
    SCHEDULED: <2014-06-26 Thu>
    :PROPERTIES:
    :Effort:   1w
    :allocate: dev
    :task_id: cc
    :BLOCKER:  aa,bb
    # :start: 2014-05-30
    :END:
* Resources                                            :taskjuggler_resource:
** Developer
  :PROPERTIES:
  :resource_id: dev
  :resource_email: address@hidden
  :END: