Change settings database/username to database/user

[dlebauer]

since R arguments use partial matching, user will work for both the MySQL and PostgreSQL drivers.

Need to

1. Update wiki page (https://github.com/PecanProject/pecan/wiki/PEcAn-Configuration#functions)
2. find and update all test settings files: find . -name "*.xml" | xargs grep username

related to redmine 1860

[dlebauer]

Here they all are. Presumably I could just pass a sed 's/username/user/g instead of grep username below. .. that doesn't exactly work...

desktop:~/R-dev/pecan$ find . -name "*.xml" | xargs grep username
./db/inst/tests/pecan.xml:    <username>bety</username>
./db/inst/tests/pecan.sipnet.xml:    <username>bety</username>
./models/biocro/vignettes/pecan.xml:  <username>bety</username>
./models/biocro/inst/extdata/saof.xml:    <username>bety</username>
./models/biocro/inst/extdata/pecan.biocro.xml:    <username>bety</username>
./models/biocro/inst/extdata/pecan.xml:  <username>bety</username>
./models/biocro/inst/tests/pecan.xml:  <username>bety</username>
./utils/inst/extdata/test.settings.xml:    <username>bety</username>
./utils/inst/tests/pecan.xml:  <username>bety</username>
./pecan.xml:  <username>bety</username>
./tests/pecan.dalec.xml:    <username>bety</username>
./tests/pecan.biocro.xml:    <username>bety</username>
./tests/pecan.ed.xml:  <username>bety</username>
./tests/pecan.xml:    <username>bety</username>
./tests/pecan.sipnet.xml:    <username>bety</username>

[robkooper]

Just as an FYI the check.settings function will do a bunch of conversions if needed and print a warning:

MySQL userid -> username user -> username

PostgreSQL userid -> user username -> user

Both passwd -> password name -> dbname

[dlebauer]

Since R uses partial matching, an argument user will match both the user and username arguments of RPosgreSQL and RMySQL, respectively. If we change 'username' to user, we will would only have to do userid -> user, and this is database agnostic. I will also simplify the check.settings function