Fixes for deprecated Matrix calls and for forthcoming Matrix 1.4-2

[kbenoit]

• fixes deprecated as() calls (mostly as(., "dgCMatrix") which we'd used a lot)
• turns on errors for using deprecated versions using options(Matrix.warnDeprecatedCoerce = 2) in testthat.R
• works for forthcoming Matrix 1.4.2 release (tested from r-forge installation)

[kbenoit]

Tests above are failing but it does pass cleanly with Matrix 1.4-2. I need to test more with current CRAN release of Matrix too.

[codecov]

Codecov Report

Merging #2182 (4cc347b) into master (9a06c2b) will increase coverage by 0.00%.
The diff coverage is 100.00%.

@@           Coverage Diff           @@
##           master    #2182   +/-   ##
=======================================
  Coverage   96.43%   96.43%           
=======================================
  Files          87       87           
  Lines        5099     5100    +1     
=======================================
+ Hits         4917     4918    +1     
  Misses        182      182           

Impacted Files	Coverage Δ
R/dfm-classes.R	94.73% <ø> (ø)
R/convert.R	93.33% <100.00%> (ø)
R/dfm-methods.R	97.05% <100.00%> (ø)
R/dfm.R	99.04% <100.00%> (ø)
R/dfm_group.R	98.46% <100.00%> (ø)
R/dfm_weight.R	95.68% <100.00%> (ø)
R/fcm-methods.R	91.89% <100.00%> (-0.42%)	⬇️
R/fcm.R	100.00% <100.00%> (ø)
R/object-builder.R	91.91% <100.00%> (ø)

Help us with your feedback. Take ten seconds to tell us how you rate us. Have a feature suggestion? Share it here.

[koheiw]

Looks good to me. Thank you for your work.