Unknown error in RForcecom 1.1 that's not present in 0.8

[BriBecker]

I'm receiving the following error when I attempt to query using newer versions like 1.1:

Error in t.default(unlist(x[setdiff(seq.int(length(x)), c(list_col, attr_col))])) : 
  argument is not a matrix

I can't say for sure when this occurs, although it appears to happen more frequently when I join objects? Here's one SOQL I just tried to run:

"SELECT Account.Id, Account.field_1__c,
Account.field_2__c, Account.field_3__c, 
Account.field_4__c,
Account.field_5__c 
FROM Contract 
WHERE Status = 'Activated' 
AND Account.field_1__c != NULL"

---

sessionInfo() returns

R version 3.3.0 (2016-05-03)
Platform: x86_64-apple-darwin13.4.0 (64-bit)
Running under: OS X 10.11.6 (El Capitan)

locale:
[1] en_US.UTF-8/en_US.UTF-8/en_US.UTF-8/C/en_US.UTF-8/en_US.UTF-8

attached base packages:
[1] stats     graphics  grDevices utils     datasets  methods   base     

other attached packages:
[1] RForcecom_1.1

loaded via a namespace (and not attached):
[1] httr_1.1.0        plyr_1.8.4        R6_2.1.2         
[4] rsconnect_0.4.1.4 tools_3.3.0       RCurl_1.95-4.8   
[7] Rcpp_0.12.5       bitops_1.0-6      XML_3.98-1.4     

---

PS: Thanks for the great work so far with this package, this enables me to make great automated reports and dashboards :)

[StevenMMortimer]

@BriBecker I hope to have fixed this issue with #51, but figured I'd respond with a workaround for others while waiting for the PR to be reviewed.

The issue with your query was that it queries the Contract object but only asks for fields from the parent Account object. A quick workaround would be to include at least 1 field from the Contract object. That should solve the issue.