defines XML/S4 coercions for citation class, corrects them for article class #27
Represents the work of 5 commits

Fixes the atomic class slot names

o now all slot names of the atomic classes for the citation types
  are named after the class.

Puts "citation" slot in place for "eml"

This is related to issue #27

Adds more coercion methods for literature classes

o This belongs to issue #27

Changes documentation and inclusion

o Adds the modules to be included into the literature module
	- adds modules already there for inclusion
o changes the citation prototype in comments

defines XML/S4 coercions for citation class, corrects them for article class #27
Merge pull request #73 from cpfaff/litrature

Fixes XML coercion definitions for literature module
- makes class slot names match definitions (for all complex types)
- fixes coercion definitions, using S4Toeml where appropriate
- defines missing coercion definitions
- Also adds citation class as a slot for the eml module (eml.R)
Adds working version of bib entry mapping

o Uses setAs now as it is a coercion method
o See working example below.

```coffee
b <- new("article")
c <- new("ListOfcreator", firstName = "test")
j <- new("journal", journal = "Testjournal")
v <- new("volume", volume = "1")

b@creator = c
b@title = "the title"  # So that the entry isn't empty
b@journal = j
b@pubDate = "Test"

b@volume = v

as(b, "XMLInternalElementNode")
theentry = as(b, "bibentry")

print(theentry)

print(theentry, style = "citation")
print(theentry, style = "html")
print(theentry, style = "bibtex")
print(theentry, style = "R")
```

Belongs to issue #27
Merge pull request #74 from cpfaff/litrature

Adds a mostly working version of bib entry mapping for article
fixed typo in a slotName
Merge branch 'master' of github.com:ropensci/reml
fixed coersion person to individualName: person needs S3 slot referencing
fix a few typos, example should actually run
add convenience function for constructing eml responsibleParty types
define concatenate methods for all ListOf classes; closes #67
create a packageId in eml prototype
includes a test case to make sure this doesn't overwrite identifiers read in when coercing XML to S4
eml_read gets the namespaces from the file, rather than the default namespaces
updated documentation
update roxygen, avoid error of '@' used in email
remove depricated test
add id get method to read example list
docs
rearrange definitions, depricate and prepare to depricated outdated methods
method for generating keywordSet node from list