corrected a few grammatical errors

other comments were detailed in an email to Tim
Merge pull request #13 from astronomeralex/few-grammatical-changes

corrected a few grammatical errors
Add missing doi
Cite a paper discussing of once FITS, always FITS rule
Note we are inconsistent in always vs forever
Greisen 2003 discusses the hierarchical grouping issue
Add new author: Paul Hartogh
Merge pull request #14 from migueldvb/local

Add new author: Paul Hartogh
Add author: Klaes
Dispense with footnote on forever FITS and cite V1 of standard properly
Fix quoting of title
Allow line breaks of URLs

Some of the URLs were causing trouble because of their length
Put Library of Congress document in references
Move CONTINUE to references section

To be consistent with HIERARCH
Should be citep not cite
fix spacing after period in e.g.
Suggest reformulating last part of 2.1.4 as a critique of FITS, not
a requirement for a new format.
Remove extra space in citep command
Use comma after i.e. to be consistent with American English spelling
Add author: Craig