Adapt to new SMILES names at PubChem

This may break some code using the old smiles names "PubChem_Canonical"
and "PubChem_Isomeric" instead of the new smiles names "PubChem"
(including isotopic and stereochemical information) and
"PubChem_Connectivity" (only containing connectivity, but still
canonical).

Further changes in this commit:
- A fix to the test target in the makefile
- Use markdown syntax for link to objects from other packages in the
  documentation
- Adapt the tests
- Increase test coverage a bit

1 files changed, 1 insertions, 1 deletions

diff --git a/man/ppp.Rd b/man/ppp.Rd
index 4e456c4..a01b3bb 100644
--- a/man/ppp.Rd
+++ b/man/ppp.Rd
@@ -4,7 +4,7 @@
 \alias{ppp}
 \title{R6 class for a plant protection product with at least one active ingredient}
 \format{
-An \code{\link{R6Class}} generator object.
+An \link[R6:R6Class]{R6::R6Class} generator object.
 }
 \description{
 Contains basic information about the active ingredients in the