Fix some issues to work on my ceiba

[b04505009]

I fixed some issues in your project and removed some assertion based on my ceiba courses.

New features

• Make sure the file path would be correct before creating file by library pathvalidate

Unexpected conditions on my ceiba

• 成績分佈 has 公佈全班 attribute, which is a link for whole class' grade
• 旁聽 courses is on table 2
• I have time slot with space value (' ') for my 暑期實習
• Students from NTNU or NTUST may not have all 12 rows in their pages
• I have a course that it's 課程助教 is plain text

[lantw44]

抱歉過了這麼久才回來看，有些關於 commit 的問題希望可以先解決：

1. 你的 4 個 commit 的作者不一致，建議改成一樣的。如果不改的話，我會幫你改成可以對得到 GitHub 帳號的那個。

Author:     b04505009 <[email protected]>
Author:     b04505009 <[email protected]>
Author:     b04505009 <[email protected]>
Author:     b04505009 <[email protected]>

2. 請不要修改檔案屬性，ceiba_dl 資料夾裡的檔案不該是可執行檔。

diff --git a/ceiba_dl/__init__.py b/ceiba_dl/__init__.py
old mode 100644
new mode 100755
diff --git a/ceiba_dl/config.py b/ceiba_dl/config.py
old mode 100644
new mode 100755
diff --git a/ceiba_dl/vfs.py b/ceiba_dl/vfs.py
old mode 100644
new mode 100755

3. 除非你的 commit 會影響整個專案，不然請用「分類: 標題」的格式寫 commit 訊息。為了讓專案內的 commit 訊息格式一致，建議寫的時候可以參考一下現有的 commit。