This is related to a currently opened bug on Selendroid Class resolved by unexpected DEX error · Issue #721 · selendroid/selendroid · GitHub
The issue is that the new version of Selendroid 0.11.0 and newer, uses the Gson library and probably your Android app does as I can see in your logcat log:
W/dalvikvm(10203): Class resolved by unexpected DEX: Lcom/foo/modules/ApiModule;(0x42068960):0x58b33000 ref [Lcom/google/gson/GsonBuilder;] Lcom/google/gson/GsonBuilder;(0x42068960):0x57a62000
W/dalvikvm(10203): (Lcom/foo/modules/ApiModule; had used a different Lcom/google/gson/GsonBuilder; during pre-verification)
They are currently working on removing that dependency in order to get things working again.
A possible work around for now is to use older Selendroid versions 0.10.0 or older.