BUG/API: remove infer_types from replace and fix compiled regex bug

[cpcloud]

closes #3907.

[cpcloud]

@jreback merge-able? i can remove _is_sequence in a later pr if u want but that is low priority...

[cpcloud]

u know what let me add some tests for the things i added to common.py

[jreback]

did Travis check this?

[cpcloud]

it did but i just pushed another commit so rerunning :|

[cpcloud]

(passed the first time)

[cpcloud]

ok now it's ready

[jreback]

ok just recall if I changed something really low level sometimes things break

[cpcloud]

oh. what did u change that is low-level?

[jreback]

no was a while ago

[cpcloud]

ah len is there for StringMethods. putting it back...

[cpcloud]

and i will write a test so that someone doesn't take it out in the future

[cpcloud]

although a test still passes because of my addition of __iter__ to StringMethods a while back. i'm just going to add the test and keep len out of is_list_like

[cpcloud]

oh i also need 2 change the replace docs i think...

[cpcloud]

nope nothing about infer_types in there

[cpcloud]

ok build is passing.

[cpcloud]

@jreback merge-able round 2?

[jreback]

looks good
very minor point - can u put next to where (or even include) as part of your other replace changes in release notes - then they r all together