Improve collecting module

Related to #8.
I should change recipe of melpa for including this perl script If I apply this patch.

#### before
![helm-perldoc-old](https://f.cloud.github.com/assets/554281/2342877/26e52574-a502-11e3-8b0e-4b781c8a63ff.png)


#### after
![helm-perldoc-new](https://f.cloud.github.com/assets/554281/2342880/2f850532-a502-11e3-806c-f54659b38b26.png)

ping @sugyan